Blackberry Crumble

It is the last of the season and the blackberries are ripe.  At my sweetheart's work I had a request for some blackberry crumble.  This is great with a scoop of ice cream or spoonful of whipped cream on top.
Topping:

• 1 1/2 cup old-fashioned oats
• 1 cup  flour
• 1 cup  brown sugar
• 1/4 t. salt
• 1 c.  butter, cut into small pieces

Fruit:

• 8-10 cups fresh blackberries
• 1/2 cup sugar
• 1/2 cup flour
• 1 T. lemon juice

In a large bowl mix blackberries with other fruit ingredients.  Spray a 13 x 9 baking dish with cooking spray.  Put all the fruit ingredients into the baking dish.   Combine the  oats, flour, brown sugar, and salt.  Add butter and using a pastry blender, cut the butter into small pieces into the mixture.  Spoon this mixture on top of the fruit.  Bake at 350 degrees for 45 minutes.